The present invention relates to a method of and an arrangement for supplying a granular or pulverized fuel to several burners of a furnace.
In certain industrial furnaces provided with several burners, such as for example a double regeneration furnace for burning lime, it is necessary from process technology considerations to retain constant the amount of fuel burner per time unit and thereby the heat balance of the furnace. This was possible only in the condition of operation of the furnace with gaseous and liquid fuels. In contrast, the utilization of granular and pulverized fuels, particularly pulverized coal, failed despite the price advantages as compared with heating gas or heating oil because of the insufficient dosing accuracy, and despite the fact that generally it is known to supply the burner of a furnace with granular or pulverized fuel. The fuel is discharged from a supply container with the aid of a discharge element and pneumatically supplied via a supply conduit to collectors provided for each burner, whereupon the fuel is discharged from the collector via a dosing element to the pressure supply conduit of a respective burner. The quantity of burned fuel can change in dependence upon the discharge output of the dosing elements, for example upon change of the number of revolutions of a cellular wheel sluice or a dosing screw. The required control signal can be supplied to a differential scale on which the collector is mounted, and its weight reduction per unit time can be determined and compared with an actual value.
For the application in the above mentioned field, the above described arrangement is not suitable because, in addition to the fact that the introduction of differential scales for each collector and each burner is very expensive, the unavoidable dosing errors of the individual dosing elements add to an entire error which considerably exceeds the allowable deviation of the consumed fuel quantity per time unit from the predetermined fuel quantity.